Oil fume catalytic coating as well as preparation method and application thereof

Abstract

The oil fume catalytic coating is characterized in that the oil fume catalytic coating is prepared from AgRu, CoCe-coated C3N4 and black F-La-TiO2, the CoCe-coated C3N4 is a cobalt-cerium compound coated with carbon nitride, and the black F-La-TiO2 is TiO2 co-doped with elements F and La. The invention further discloses a preparation method and application of the oil fume catalytic coating. The coating disclosed by the invention has the characteristics of low cost and high-performance catalysis, can fully utilize the auxiliary excitation effect of an internal heat source and a light source at the actual cooking temperature of the steaming and baking oven, and realizes efficient purification of oil fume peculiar smell; meanwhile, precious metal catalytic components are replaced, the technical cost is reduced, and the practical application economic value is met.

Description

Technical Field

[0001] The present invention relates to a coating for fume purification, which is applied to electrical appliances such as ovens, refrigerators, air purifiers, etc. The present invention also discloses a preparation method and specific application of the coating. Background Art

[0002] In actual family life, the generation of fumes in the oven is a headache problem. A large amount of fume odor will be emitted during the cooking process and when opening the door. Therefore, the purification of fumes generated by the oven has increasingly become the focus of attention of families and product manufacturers. At present, fume purification is mainly solved by technical means such as adsorption filtration and oxidation decomposition.

[0003] The filtration technology mainly intercepts fume particles with a HEPA net (also called a high-efficiency particulate filter net), etc. This method can effectively filter a part of the fumes, but it cannot remove the fume odor of gaseous components, and the purification is not thorough; in addition, the service life of the filter net of this method is short and needs to be replaced regularly, and the customer experience is relatively low.

[0004] The decomposition technology mainly uses means such as catalytic oxidation to directly decompose fume molecules into carbon dioxide and water, so as to achieve the purpose of removing fumes. In addition, compared with the filtration and interception method, the service life of this technology is longer. However, it should be noted that in the actual oven use environment, the temperature is mostly below 250°C, while general catalysts require a higher catalytic temperature to have high purification ability. Therefore, this technology needs to develop high-performance catalysts at lower temperatures. Summary of the Invention

[0005] The first technical problem to be solved by the present invention is to provide a fume catalytic coating that can utilize the auxiliary excitation effect of the internal heat source and light source of the electrical appliance in view of the above technical status.

[0006] The second technical problem to be solved by the present invention is to provide a preparation method of a fume catalytic coating that can utilize the auxiliary excitation effect of the internal heat source and light source of the electrical appliance in view of the above technical status.

[0007] The third technical problem to be solved by the present invention is to provide an application of a fume catalytic coating that can utilize the auxiliary excitation effect of the internal heat source and light source of the electrical appliance in view of the above technical status.

[0008] The technical solution adopted by the present invention to solve the above first technical problem is: a fume catalytic coating, characterized in that the fume catalytic coating includes AgRu, CoCe@C3N4, and black F-La-TiO2;

[0009] The total loading amount of Ag relative to the coating is 0.1% - 3%, and the total loading amount of Ru relative to the coating is 0.1% - 1%;

[0010] CoCe@C3N4 is a cobalt-cerium composite coated with carbon nitride. The total loading of CoCe relative to black F-La-TiO2 is 0.5-10%, the Co / Ce atomic ratio is 0.001-0.1, the precursor of C3N4 is urea, and the addition ratio of urea to black F-La-TiO2 is 0.01-0.1;

[0011] Black F-La-TiO2 is TiO2 co-doped with F and La elements. The molar ratio of F to TiO2 is 0.01-0.1, and the loading of La relative to TiO2 is 0.1-1%.

[0012] Preferably, the total loading of Ag relative to the coating is 0.5%-2%, and the total loading of Ru relative to the coating is 0.1%-0.6%; CoCe@C3N4 is a cobalt-cerium composite coated with carbon nitride. The total loading of CoCe relative to black F-La-TiO2 is 1-6%, the Co / Ce atomic ratio is 0.01-0.08, and the addition ratio of urea to black F-La-TiO2 is 0.01-0.08.

[0013] The technical solution adopted by the present invention to solve the above second technical problem is: a preparation method of an oil fume catalytic coating, which is characterized by including the following steps:

[0014] ① Preparation of black TiO2 co-doped with F and La: Dissolve tetrabutyl titanate in absolute ethanol and stir at room temperature until dissolved. Then disperse NH4F in absolute ethanol to obtain a mixed solution A; dissolve lanthanum nitrate, C2H6O2 and deionized water in ethanol to obtain a solution B; slowly add solution B dropwise to mixed solution A and continuously stir until a sol is formed. Let the obtained sol stand at room temperature to obtain a gel, dry it, calcine it under an anoxic state, and grind it to obtain black F-La-TiO2 powder;

[0015] ② Disperse the Ce source, Co source and urea in water, add black F-La-TiO2 powder to form a uniform dispersion, and finally add a certain amount of aluminum sol and stir well to form a uniformly mixed slurry. Coating it on a porous honeycomb ceramic substrate or a foam ceramic by vacuum coating, drying it, and calcining it under an anoxic state to obtain a ceramic substrate coated with a composite carrier;

[0016] ③ Disperse the Ag source and Ru source in water to form a uniform dispersion, and then impregnate and disperse the Ag and Ru sources on the ceramic coating by the impregnation method, dry it, and calcine it under an anoxic state to obtain the final porous honeycomb catalytic coating module.

[0017] Preferably, the calcination temperature in step ① is 300-700 °C; the calcination temperature in step ② is 400-700 °C; the calcination temperature in step ③ is 300-700 °C.

[0018] Preferably, the drying temperature in step ① is 60-180 °C, the drying temperature in step ② is 60-180 °C, and the drying temperature in step ③ is 60-180 °C.

[0019] The technical solution adopted by the present invention to solve the above-mentioned third technical problem is: the application of the oil fume catalytic coating in an oven, an odor purifier, an air purifier and a refrigerator.

[0020] Compared with the prior art, the advantages of the present invention are as follows:

[0021] For black F-La-TiO2, due to the co-doping of F and La and the oxygen-deficient calcination, a large number of oxygen vacancies are generated on it; at the same time, the introduction of F can reduce the hydrophilicity of TiO2 to a certain extent, and the presence of La can enhance the adsorption sites of TiO2; in addition, the black F-La-TiO2 support exhibits good visible light absorption characteristics and even partial infrared absorption.

[0022] CoCe@C3N4 is fully dispersed in the TiO2 support. Among them, CoCe exists in the form of a composite oxide coating a certain amount of C3N4, so that the active layer has a large specific surface area; due to the strong interaction between Co, Ce, C3N4 and the TiO2 support, the composite metal oxide has rich oxygen vacancies; in addition, the CoCe@C3N4 composite black F-La-TiO2 structure exhibits stronger visible light absorption and catalytic effects.

[0023] Since both the support and the active layer have a large specific surface area and rich oxygen vacancies, the Ag and Ru components can be highly dispersed, and at the same time, the synergistic effect of the two components is strengthened.

[0024] The active layer and the support are directly coated and formed into a composite coating by a one-pot method, combined with calcination in an oxygen-deficient state, which ensures the rich oxygen vacancies on the support and the active layer, and at the same time ensures the high dispersion of the subsequent active components; through three-step oxygen-deficient calcination, the oxygen vacancy content of the material is maximally retained.

[0025] The catalyst coating has a high specific surface area and strong adsorption sites, and can effectively adsorb oil fume particles and gaseous VOCs; secondly, due to the introduction of F and C3N4, the coating as a whole has good hydrophobicity, effectively reducing the competitive adsorption brought by H2O molecules; thus, the coating can efficiently adsorb oil fume pollutants.

[0026] A large number of oxygen vacancies on the coating, the CoCe@C3N4 active layer, and the highly dispersed Ag and Ru active components work together to generate a large amount of reactive oxygen, thereby decomposing the adsorbed pollutants. Secondly, under the irradiation of visible light and infrared light in the oven, the heterojunction generated between CoCe@C3N4 and TiO2, as well as the strong electron transfer ability of Ag and Ru, enable the efficient separation of photo-generated electrons and holes, endowing the coating with high photocatalytic activity, which can further generate reactive oxygen, avoid the accumulation of by-products, and achieve efficient photo-thermal catalytic decomposition of cooking fumes.

[0027] Considering that the heating tubes in the oven will generate heat and a large amount of infrared rays, and generally multiple LED lights are built into the inner cavity of the oven, which will also generate high-intensity visible light; therefore, the present invention develops a low-cost and high-performance catalytic coating, which can make full use of the auxiliary excitation effect of the internal heat source and light source at the actual cooking temperature of the steam oven to achieve efficient purification of cooking fume odor; at the same time, replace the noble metal catalytic components to reduce the technical cost and adapt to the actual application economic value. Specific embodiments

[0028] The following details each specific embodiment. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not intended to limit the present invention.

[0029] Example 1

[0030] The coating composition of this example is AgRu / CoCe@C3N4 / black F-La-TiO2; wherein, an F source is added at an F / Ti molar ratio of 0.05, the loading amount of La relative to TiO2 is 0.5%, the total loading amount of CoCe relative to TiO2 is 4%, the Co / Ce atomic ratio is 0.03, urea is used as the precursor of C3N4, and the addition ratio of urea to black F-La-TiO2 is 0.02; the total loading amount of Ag relative to the coating is 1%, and the total loading amount of Ru relative to the coating is 0.2%.

[0031] The coating preparation steps are divided into three steps:

[0032] (1) Preparation of F- and La-codoped black TiO2: First, dissolve a certain amount of tetrabutyl titanate in an appropriate amount of absolute ethanol, stir at room temperature until dissolved, and then disperse a certain amount of NH4F in this solution to obtain a mixed solution A. Secondly, dissolve a certain amount of lanthanum nitrate, C2H6O2 and deionized water in an appropriate amount of ethanol to obtain solution B. Finally, slowly add solution B to mixed solution A, continuously stir until a sol is formed, and let the obtained sol stand at room temperature for a period of time to obtain a gel. Dry the obtained sample and calcine it under anoxic conditions at 500 °C to obtain a black F-La-TiO2 sample.

[0033] (2) Disperse a certain amount of cerium nitrate, cobalt nitrate, and urea in water, add black F-La-TiO2 powder to form a homogeneous dispersion, and finally add a certain amount of aluminum sol and stir well to form a uniformly mixed slurry. Coating the porous honeycomb ceramic substrate or foam ceramic by vacuum coating method, drying, and calcining under anoxic conditions at 500 °C to obtain the ceramic substrate coated with the composite support.

[0034] (3) Disperse silver nitrate and ruthenium nitrate in water to form a homogeneous dispersion, and then impregnate and disperse the Ag and Ru sources on the ceramic coating by the impregnation method, dry at 120 °C, and calcine under anoxic conditions at 500 °C to obtain the final porous honeycomb catalytic coating module.

[0035] Example 2

[0036] In this example, the F source is added with an F / Ti molar ratio of 0.05, and the rest of the operations are the same as those in Example 1.

[0037] Example 3

[0038] In this example, the loading amount of La relative to TiO2 is changed to 0.1%, and the rest of the operations are the same as those in Example 1.

[0039] Example 4

[0040] In this example, the total loading amount of CoCe relative to TiO2 is changed to 0.5%, and the rest of the operations are the same as those in Example 1.

[0041] Example 5

[0042] In this example, the Co / Ce atomic ratio is changed to 0.001, and the rest of the operations are the same as those in Example 1.

[0043] Example 6

[0044] In this example, the ratio of urea to the addition amount of black F-La-TiO2 is changed to 0.005, and the rest of the operations are the same as those in Example 1.

[0045] Example 7

[0046] In this example, the total loading amount of Ag relative to the coating is changed to 0.1%, and the rest of the operations are the same as those in Example 1.

[0047] Example 8

[0048] In this example, the total loading amount of Ru relative to the coating is changed to 0.1%, and the rest of the operations are the same as those in Example 1.

[0049] Example 9

[0050] The coating composition of this example is mainly AgRu / CoCe@C3N4 / black F-La-TiO2; among them, an F source is added at an F / Ti molar ratio of 0.1, the loading amount of La relative to TiO2 is 2%, the total loading amount of CoCe relative to TiO2 is 10%, the Co / Ce atomic ratio is 0.1, and the addition ratio of urea to black F-La-TiO2 is 0.05; the total loading amount of Ag relative to the coating is 0.1%, and the total loading amount of Ru relative to the coating is 0.1%; in the preparation step (1), it is calcined under oxygen-deficient conditions at 300 °C, in step (2), it is calcined under oxygen-deficient conditions at 400 °C, and in step (3), it is calcined under oxygen-deficient conditions at 300 °C; the remaining operations are the same as those in Example 1.

[0051] Example 10

[0052] The coating composition of this example is mainly AgRu / CoCe@C3N4 / black F-La-TiO2; among them, an F source is added at an F / Ti molar ratio of 0.01, the loading amount of La relative to TiO2 is 0.1%, the total loading amount of CoCe relative to TiO2 is 0.5%, the Co / Ce atomic ratio is 0.001, and the addition ratio of urea to black F-La-TiO2 is 0.005; the total loading amount of Ag relative to the coating is 3%, and the total loading amount of Ru relative to the coating is 1%; in the preparation step (1), it is calcined under oxygen-deficient conditions at 700 °C, in step (2), it is calcined under oxygen-deficient conditions at 700 °C, and in step (3), it is calcined under oxygen-deficient conditions at 700 °C; the remaining operations are the same as those in Example 1.

[0053] Comparative Example 1

[0054] The catalytic coating of this comparative example is only TiO2; a uniform dispersion liquid of TiO2 powder is formed, a certain amount of aluminum sol is added, and it is fully stirred to form a uniformly mixed slurry, which is coated on a porous honeycomb ceramic substrate or a foam ceramic by vacuum coating, dried, and calcined under oxygen-deficient conditions at 500 °C to obtain a ceramic substrate coated with a composite support.

[0055] Comparative Example 2

[0056] The catalytic coating of this comparative example is only Ce / TiO2, and the total loading amount of Ce relative to TiO2 is 4%; a uniform dispersion liquid of a certain amount of cerium nitrate and TiO2 powder is formed, and finally a certain amount of aluminum sol is added, and it is fully stirred to form a uniformly mixed slurry, which is coated on a porous honeycomb ceramic substrate or a foam ceramic by vacuum coating, dried, and calcined under oxygen-deficient conditions at 500 °C to obtain a ceramic substrate coated with a composite support.

[0057] Comparative Example 3

[0058] The catalytic coating in this comparative example is only Ag / TiO2, and the Ag loading relative to TiO2 is 1%; TiO2 powder is formed into a uniform dispersion, and finally a certain amount of aluminum sol is added and fully stirred to form a uniformly mixed slurry, which is applied to a porous honeycomb ceramic substrate or foam ceramic by vacuum coating, dried, and calcined at 500°C in an oxygen-deficient state to obtain a ceramic substrate coated with a composite carrier; silver nitrate and ruthenium nitrate are dispersed in water to form a uniform dispersion, and then Ag and Ru sources are impregnated and dispersed on the ceramic coating by an impregnation method, dried at 120°C, and calcined at 500°C in an oxygen-deficient state to obtain the final porous honeycomb catalytic coating module.

[0059] Comparative Example 4

[0060] The catalytic coating in this comparative example is only Ag / CeO2 / TiO2, with the total loading of Ce relative to TiO2 being 4%, and the loading of Ag relative to TiO2 being 1%; a certain amount of cerium nitrate and TiO2 powder is formed into a uniform dispersion, and finally a certain amount of aluminum sol is added and fully stirred to form a uniformly mixed slurry, which is applied to a porous honeycomb ceramic substrate or foam ceramic by vacuum coating, dried, and calcined at 500°C in anoxic conditions to obtain a ceramic substrate coated with a composite carrier; silver nitrate and ruthenium nitrate are dispersed in water to form a uniform dispersion, and then the Ag and Ru sources are impregnated and dispersed on the ceramic coating by an impregnation method, dried at 120°C, and calcined at 500°C in anoxic conditions to obtain the final porous honeycomb catalytic coating module.

[0061] The catalytic modules prepared in the embodiment and the comparative example were placed in purification devices with the same parameters, and tested in the same oven and operating program. A certain amount of cooking oil was roasted in the oven, the cooking temperature was set at 200°C, the time was set at 30 minutes, a certain concentration of oil smoke was generated, and then the purification was turned on for a fixed time to test the oil smoke purification effect.

[0062]

[0063]

[0064] First of all, it should be noted that although in the following description, the coating of the present invention can be typically used in an oven fume purification environment, the present invention is not limited to this. The catalytic coating can be used in occasions and equipment that require odor removal and purification, such as odor purifiers, air purifiers, etc., which all fall within the scope of protection of the present invention.

Claims

1. An oil fume catalytic coating, characterized in that The oil fume catalytic coating includes AgRu, CoCe@C3N4, and black F-La-TiO2; The total loading amount of Ag relative to the coating is 0.1% to 3%, and the total loading amount of Ru relative to the coating is 0.1% to 1%; CoCe@C3N4 is a cobalt-cerium composite coated with carbon nitride. The total loading amount of CoCe relative to black F-La-TiO2 is 0.5 to 10%, the Co / Ce atomic ratio is 0.001 to 0.1, the precursor of C3N4 is urea, and the addition ratio of urea to black F-La-TiO2 is 0.01 to 0.1; Black F-La-TiO2 is TiO2 co-doped with F and La elements. The molar ratio of F to TiO2 is 0.01 to 0.1, and the loading amount of La relative to TiO2 is 0.1 to 1%.

2. The oil fume catalytic coating according to claim 1, wherein The total loading amount of Ag relative to the coating is 0.5% to 2%, and the total loading amount of Ru relative to the coating is 0.1% to 0.6%; CoCe@C3N4 is a cobalt-cerium composite coated with carbon nitride. The total loading amount of CoCe relative to black F-La-TiO2 is 1 to 6%, the Co / Ce atomic ratio is 0.01 to 0.08, and the addition ratio of urea to black F-La-TiO2 is 0.01 to 0.

08.

3. The preparation method of the oil fume catalytic coating according to claim 1 or 2, characterized in that It includes the following steps: ① Preparation of black TiO2 co-doped with F and La: Dissolve tetrabutyl titanate in absolute ethanol and stir at room temperature until dissolved. Then disperse NH4F in absolute ethanol to obtain a mixed solution A; dissolve lanthanum nitrate, C2H6O2, and deionized water in ethanol to obtain a solution B; dropwise add solution B into mixed solution A and continuously stir until a sol is formed. Let the obtained sol stand at room temperature to obtain a gel, dry it, calcine it under an oxygen-deficient state, and grind it to obtain black F-La-TiO2 powder; ② Disperse the Ce source, Co source, and urea in water, add black F-La-TiO2 powder to form a uniform dispersion, and finally add a certain amount of aluminum sol and stir well to form a uniformly mixed slurry. Coating it on a porous honeycomb ceramic substrate or foam ceramic by vacuum coating, drying it, and calcining it under an oxygen-deficient state to obtain a ceramic substrate coated with a composite support; ③ Disperse the Ag source and Ru source in water to form a uniform dispersion, and then impregnate and disperse the Ag and Ru sources on the ceramic coating by the impregnation method, dry it, and calcine it under an oxygen-deficient state to obtain the final porous honeycomb catalytic coating module.

4. The preparation method according to claim 3, characterized in that The calcination temperature in step ① is 300 to 700 °C; the calcination temperature in step ② is 400 to 700 °C; the calcination temperature in step ③ is 300 to 700 °C.

5. The preparation method according to claim 3, characterized in that The drying temperature in step ① is 60 to 180 °C, the drying temperature in step ② is 60 to 180 °C, and the drying temperature in step ③ is 60 to 180 °C.

6. Application of the oil fume catalytic coating described in claim 1 or 2 in an oven, odor purifier, air purifier, and refrigerator.

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